Lady Gaga and Prince William team up for mental health campaign

Lady Gaga and British royal Prince William have teamed up to encourage mental health sufferers to speak out about their issues.

The "Born This Way" singer was filmed having a FaceTime conversation with the Duke of Cambridge to discuss how she felt about being open about her struggles with mental health issues, including post traumatic stress disorder (PTSD), and how important it was to talk about it.

"It made me very nervous at first," she said, speaking from the kitchen of her Los Angeles home. "There's a lot of shame attached to mental illness - you feel like something's wrong with you. In my life I go, 'oh my goodness, look at all these beautiful, wonderful things that I have' and I should be so happy but you can't help it if in the morning when you wake up you are so tired, you are so sad, you are so full of anxiety..."

Prince William suggested other sufferers should be as open as the singer because it will help break the stigma attached to mental health and can make a huge difference to each person, who could suffer more further down the line if they keep quiet.

Gaga agreed, saying, "Even though it was hard, the best thing that could come out of my mental illness was to share it with other people and let our generation as well as other generations know that if you are feeling not well in your mind, that you're not alone... we have to make the strongest, most relentless attempt we can to normalise mental health issues so that people feel like they can come forward."

Prince William ended the conversation by asking her to visit his royal residence Kensington Palace when she visits London on tour later this year. He also thanked her for supporting the Heads Together campaign, which is also championed by his brother Harry and wife Catherine, Duchess of Cambridge.

Sharing their video, Gaga tweeted, "Thanks to Prince William & @heads_together for inviting me to join this important conversation around mental health awareness #oktosay."

Their video came just days after Prince Harry confessed he shut down his emotions and refused to think about his mother Princess Diana's death in 1997, when he was aged 12.